Electrical controlling apparatus and method



p 1938. E. E. LITTLEFIELD 2,129,331

ELECTRICAL CONTROLLING APPARATUS AND METHOD Filed May 23, 1923 Patented Sept. 6, 1938 UNITED STATES PATENT OFFICE ELECTRICAL CONTROLLING APPARATUS AND METHOD 10 Claims.

This application is a continuation, in part, of the following applications: application Ser. No. 328,305, filed Oct. 3, 1919; application Ser. No. 54,080, filed Sept. 2, 1925; application Ser. No.

4,102, filed Jan. 22, 1925; which applications, by

reference, are made a part hereof, said applications having resulted in Patents 1,709,083, 1,862,937 and 1,893,627 respectively.

This invention relates to an electrical system of the type having a translating device arranged on the primary side of inductive impedance in the form of atransforipr, or similar device, and which translating deviii 'is controlled by appropriate means on the secondary side of the impedance. In certain cases, as will be explained later, a translating device may be arranged on the secondary side of the impedance and controlled from the primary side; Preferably the voltage of the current supplied to the secondary side of the impedance is sufficiently low to prevent arcing or heating of contact points and, moreover, enables it to be manipulated or controlled with safety.

Numerous advantages and objects will appear from the following description taken in connection with the accompanying drawing in which Fig. 1 illustrates, diagrammatically, a translating device arranged on the primary side of an impedance and. controlled by means of a rheostat, or 30 equivalent device, on the secondary side. Fig. 2

I shows a modified embodiment in which the translating device takes the form of a valve or motor for controlling a supply of fluid, the circuit ofthe valve being controlled by means of a relay included in the secondary circuit. In this embodiment a thermostatic switch is substituted for a rheostat control. In Fig. 3 is shown a flushing system embodying my invention but having a modified circuit arrangement.

In the various views like numerals refer to like parts.

Referring to Fig. 1, 1 represents an impedance having a low tension secondary circuit l9 which includes a rheostat 20 for which may be substi- 45 tuted, when necessary or desirable, any other equivalent device. The primary circuit of this impedance includes a translating device 2 of any desirable form or type and a source of alternating current 3. Obviously, current from an ordinary service main may be employed to energize the primary circuit 24 instead of that supplied by the generator 3. For many purposes I have found 24 volts a safe and desirable voltage for the secondary circuit, while the primary voltage may be practically anything desired, depending upon the purpose the apparatus is designed to serve. Assuming that the circuits are closed, it will be apparent that current will flow to the impedance and the flow of this current may be regulated by the rheostat, the operation of the translating device being controlled by the latter.

In Fig. 2-I have shown a modified embodiment in which 61 represents an impedance having a low tension secondary winding 84 to which is connected a secondary circuit 13 which contains a relay l0 and a thermostatic controlling device '18. The action of this thermostatic device may be dependent upon the temperature of a com-, partment or room in which the same may be located. To the primary winding 85 of the impedance is connected a high tension primary circuit II, it being assumed that the primary winding 85 is of a high tension type. A suitable source of alternating current 68 is included in circuit ll while a switch element 14 permits the circuit to be interrupted when necessary or desirable. A branch circuit 12, controlled by the relay 10, contains a fluid supply controlling means 69 by means of which a flow of fluid, such as water, air, steam, gas or oil, through the supply line I may be controlled. By utilizing low voltage in the secondary circuit oi'the impedance a considerable saving is effected in the cost of installation, since the thermostatic device is often located some distance from the impedance. Moreover, by employing low voltage, arcing at the contact points. of the thermostat is minimized or eliminated. In the arrangement disclosed in Fig. 2 I have shown a system which is particularly adapted for use in heating systems in which the thermostatic controlling device 18 may be located in a room remote from the furnace and fuel supply, the two latter being omitted from the drawing but being understood to form component parts of the system. While I have shown the thermostatic device 18 in open position it will be understood that as employed to control the temperature of a compartment or room the circuit which it controls is normally closed. In other words, the operation of the thermostatic device depends upon the temperature of the room or compartment, the circuit through the former being interrupted upon a rise in temperature above a certain point and completed again upon a dropping in the temperature below such point. Assuming that the thermostat 18 has responded to an increase in the temperature of its surroundings, the temperature of the air of a room for instance, the circuit through it will be interrupted as shown in the drawing. At such time the relay 10 will open, as shown, interrupting branch circuit 12, thus cutting oil the heating medium, in the form of gas or oil, controlled by the means shown at 69. Obviously, upon a dropping of the temperature of the compartment below a certain point the current through the thermostat will be restored, resulting in the supply of heating medium being replenished, thus restoring the desired temperature to the compartment. It is apparent that such a system may be utilized in connection with a refrigeration system, thus finding an additional use. In such a system the thermostatic device would be so arranged in a compartment of the system as to control either the starting of the refrigerating machine or the flow of cooling brine to the refrigerating compartment, the functioning of the thermostatic device depending upon the temperature of the compartment in which it is located.

I also contemplate that the translating device 08 may take the form of a time-controlled circuit controlling device by means of which branch circuit 12 may be interrupted at predetermined times and the same used in connection with electrically controlled irrigation systems. In this case an electrically controlled fluid supply valve maybe substituted for the thermostatic device 18 and the relay Ill connected for actuation by branch circuit 12 instead of by circuit 13. In other words, in such case the position of the relay III in the two circuits would be reversed. Another convenient arrangement which finds use in electrically controlled time-clock irrigation systems is the substitution of time-controlled circuit interrupting means for the thermostatic device 18. In this case the translating device 69 would take the form of a valve for controlling the flow of irrigating water, it being understood that spray heads, etc., although not shown in the drawing, form component parts of such a system. By including the time-controlled circuit interrupting device in the low tension secondary circuit I3 not only is arcing of the contact points overcome but repairs and replacements may be made without fear of serious consequences. In connection with irrigation systems, such as those described above, it has been found that a current of 75 to 100 watts is sufllcient for operation of the water supply valve while from 15 to 24 volts has been found satisfactory for the current in the secondary circuit. Obviously, such an arrangement may be employed for controlling a. flow of fluid for any desired purpose. While in the above arrangements the primary or feeder circuit of the systems of both Fig. 1 and Fig. 2 are normally closed it will be evident that no appreciable current flows through the impedance until the reactance of the latter is overcome by the closing of the secondary circuits.

A modified circuit arrangement for an automatic urinal flushing system is shown in Fig. 3 in which the relay is omitted. In this particular embodiment of the invention the source of flushing fluid I8 is controlled by means of an electrically actuated valve l arranged on the primary side of an impedance 1 and connected to a source of alternating current by means of a circuit 21, it being evident that the current supplied by the ordinary commercial service mains of commerce may, as occasion requires, be substituted for the source of current 3'. A low tension circuit 23 connects the electrodes 2| and 22 with the impedance secondary.

The system of Fig. 1 constitutes means by which current from an ordinary service main may be gradually applied to a translating device, an electric motor or light bulb for instance, by operation of the rheostat 20 contained in the low potential secondary circuit l8. While circuit 24 is normally closed, permitting a small amount of current to normally flow to the transformer, the reactance of the latter will prevent any appreciable current passing until circuit I9 is closed, at which time current may be gradually applied to the translating device 2. It is, of course, contemplated that the current of circuit [9 will be of sufilciently low voltage to permit safe manipulation of the circuit. Such a system enables the controlling device 20 to be placed at a distance from the transformer, etc., at the same time reducing the cost of installation and overcoming the inconvenience and cost of underwriters inspections, together with the added cost thereof. Any other convenient and desirable circuit controlling device may be substituted for the rheostat 20, for instance, a time controlled device, whereby circuit I! may be controlled. Or, it may take the form of a device for controlling a flow of liquid, as water, for use in an irrigation system. Instead of controlling a flow of liquid it may be a device for controlling a flow of fuel such as gas or oil. Where such devices are substituted for the rheostat 20 and it is desired to substitute time controlled circuit controlling means for the translating device 2, a circuit controlling clock for instance, it would be desirable to arrange circuit l9 to be normally closed. In this case circuit 24 would be made and broken in response to operation of the time controlled means contained therein.

Any convenient form of thermostatic cut out device may be included in the circuits of the foregoing systems, as desired, for protecting the various devices contained therein.

While in the foregoing I have illustrated and described typical forms of preferred embodiments whereby my invention may be carried into practice it will be understood that many modiflcations in the structures employed, as well as in the elements themselves, and in the application thereof, may be made without departing from the spirit of the appended claims.

I claim:

1. An electric motor starting system adapted to control the starting of an electric motor by means of induced current, including a transformer normally connected in closed circuit relation with the current supply mains; an electric motor on the primary side of said transformer con nected in series with the primary winding of said transformer, the primary winding of the transformer being so proportioned with respect to said motor that when the secondary winding of the transformer is open circuited the counter electromotive-force set up in said primary winding will prevent the passage of suilicient current to said motor to operate the same; an electric circuit formed partly by said secondary winding and having a controlling switch therein located at a distant point, the motor being controlled by said circuit.

2. An electric motor starting system adapted to control the starting of an electric motor by means of induced current, which includes a transformer, an electric motor on the primary side thereof, the motor being normally connected in closed circuit relation with said supply mains, the primary winding of the transformer being connected in series with said motor and so proportioned with respect thereto that when the secondary winding of the transformer is open circuited the counter electromotive-force set up in said primary winding will prevent the passage of suflicient current to said motor to operate the same; means controlling the starting of said motor including an electric circuit formed partly by said secondary winding and having a controlling switch therein located at a distant point, said system permitting the electromotive-force of the induced current to be so reduced that the starting of the motor may be controlled from the secondary side of the transformer.

3. The combination, with an electric motor having the windings thereof normally connected in closed circuit relation with the supply mains, of a transformer having relatively stationary windings and having its primary win-ding connected in series with the windings of said motor and so proportioned with respect thereto that when the secondary winding of said transformer is open circuited the counter electromotive-force set up in said primary winding will prevent the passage of sumcient current to said motor to operate the same; means adapted to control the starting of said motor from the secondary side of said transformer including an electric circuit formed partly by the secondary winding of said transformer and having a controlling switch therein located at. a distant point, said means permitting the electromotive-force of the current controlling the starting of the motor to be so reduced below that of the primary winding of the transformer that the starting of the motor may be controlled from the secondary side of the transformer without overheating said starting controlling means.

4. As an article of manufacture, an electrical system including a transformer having relatively stationary windings and adapted to supply secondary current, said transformer being normally connected in closed circuit relation with the current supply mains; an electric motor on the primary side of said transformer connected in series with the primary winding of said transformer, said primary winding being so proportioned with respect to said motor that when the secondary winding of the transformer is open circuited the counter electromotive-force set up in said primary winding will prevent the passage of sufficient current to said motor to operate the same; and rheostat means on the secondary side of said transformer connected to control said secondary current, the motor being controlled from the secondary side of said transformer.

5. As an article of manufacture, an electrical system including a transformer having relatively stationary windings and adapted to supply secondary current, said transformer being normally connected in closed circuit relation with the current supply mains; an electric motor on the primary side of said transformer connected in series with the primary winding of said transformer, said primary winding being so proportioned with respect to said motor that when the secondary winding of the transformer is open circuited the counter electromotive force set up in said primary winding will prevent the passage of sumcient current to said motor to operate the same; a circuit connected to be energized by said secondary current and having a variable resistance therein located at a distant point and adapted to control said circuit.

6. As an article of manufacture, an electrical system including a transformer having relatively stationary windings and normally connected in closed circuit relation with the current supply mains; an electric motor on the primary side of said transformer connected in series with the primary winding of said transformer, the primary winding of the transformer being so proportioned with respect to said motor that when the secondary winding of the transformer is open circuited the counter electromotive-force set up in said primary winding will prevent the passage of sufiicient current to said motor to operate the same; a circuit formed partly by the secondary winding of the transformer and having a variable resistance therein located at a distant point and adapted to vary the current of the secondary winding.

7. As an article of manufacture, an electrical control system adapted to control the starting of an electric motor by means of induced current having an electromotive-force below that of the current supply mains including an impedance having relatively stationary windings and normally connected in closed circuit relation with the supply mains; an electric motor so arranged that it is capable of energization by means of said impedance, and starting controlling means including an electric circuit formed partly by the secondary winding of said impedance adapted to so reduce the electromotive-force of the secondary current that the starting of the motor may be controlled from the secondary side of said impedance without damage to the starting controlling means.

8. An electrical control system including, a transformer having fixed primary and secondary windings; an electric motor located on the primary side of said transformer; energizing means common to said motorand said transformer, said transformer being normally connected in closed circuit relation with said energizing means; a secondary circuit connected to be fed wholly through said transformer, said circuit having means therein located at a distant point adapted to manually control the starting of said motor without overheating.

9. An electrical control system including a transformer having relatively stationary windings and normally connected in closed circuit relation with the supply mains; an electric motor on the primary side of said transformer; means adapted to control the starting of said motor from the secondary side of said transformer by controlling variations inthe amount of current supplied to said motor, said means including an electric circuit formed partly by the secondary winding-oi said transformer and adapted to be controlled by means extraneous of the system, said circuit having means therein located at a distant point adapted to open and close said circuit without overheating the same.

10. The method of controlling an electric motor assembled in an electrical system so that the motor is on the primary side of a transformer having energizing means common to the motor and which transformer is normally connected in closed circuit relation with said energizing means and whose secondary winding forms part of a secondary controlling circuit which comprises controlling the current applied to the motor by means of said secondary circuit so that the current is gradually applied to the motor but without varying therelative position of the windings of the transformer.

EDGAR EARLE mm. 

